1. Field of the Invention
The present invention relates to a camera using a recording medium in which an object image obtained through a photographing optical system is electronically developed, and more particularly, to a device sensing a focusing condition of the photographing optical system.
2. Description of the Related Art
Conventionally, as disclosed in Japanese Unexamined Patent Publication No. 5-2280 and U.S. Pat. No. 5,424,156, there is known a photographic material which is directly electronically developed so that the developed visible image can be immediately obtained. In this specification, such a recording medium is referred to as an electro-developing recording material, and an electronic still camera using the electro-developing recording material is referred to as an electro-developing type camera.
In the electro-developing type camera, it is necessary that an object image obtained by the photographing optical system is focused on the recording medium. If an exclusive optical sensor is provided in the camera to perform the focusing operation, the construction of the camera becomes complex and bulky.